Even before getting to the main point, bringing that money into USA as a traveler / visitor will be a hurdle as a threshold exceeding $10,000 must be declared upon entry. Will they allow the entire 5000 OMR stack in or would that be confiscated even when declared?
Like this: after paying for the food in $, suddenly giving them more money: I’m only a visitor (as I only have foreign currency, i.e. Omani Rial in cash) being like, “Here is 5000 OMR ($13,020) for your efforts” so despite that being a lot of money, will they take it?
There are ATMs all over the place, and they usually charge about $5.00 or less. You can take up to $500.00 at a time.
You can pay with a card [debit or credit] and ass a tip that way.
%15 is a good tip, 20% is generous.